Soundguy is correct about the cap and cotter pin. Getting the wheel off is easy. Getting that tire off is a heck of a job. I changed one once on my Sears mower and it almost whooped me. You will need two tire irons and lots of dish soap to allow you to pry / slip it off the wheel. Due to the size of the rim keeping it down while you pry the tire off is very hard. :smiley_aafz: Getting it or a new one back on is just as difficult. I did it myself but another pair of hands sure would have been a help but then again with such little room to work with, it could make things more difficult.
Good Luck, you are gonna need it.